I have been on some of the largest clean coal power plants built in the last 10 years in the US,
Of course clean coal power plants were mostly designed and built before, or in only the early exploratory stages of, the rise of natural gas here in the U.S..
IMHO, since some form of fossil based fuel will still need to power us for a long transition time before renewable plants and/or nuclear fusion plants can ... I vote for the natural gas fossil based fuel.
Natural gas is much easier/cheaper to burn in a clean way than coal, and certainly much easier to transport than coal. Now that we have the natural gas, it's time for coal plants - "clean" or otherwise - to be put into the beginning stages of phase-out.